Rotary-die stripping mechanism



Aug. 29, 1967 R. J. PALLE, SR 3,333,124

ROTARY-DIE STRIPPING MECHANISM Filed Oct. 18, 19 65 /a is 44 E\ INVENTOR, ROBERT J PALLE B BY 2 ATT NEY United States Patent O Filed Oct. 18, 1965, Ser. No. 497,189 10 Claims. (Cl. 83-152) This invention relates generally to cutting apparatus, and more particularly it pertains to a mechanism for removing punched material from a rotary surface.

A rotary die cutting machine which operates by forcing a die against stock material, such as paper board backed by a resilient cushion roller often is troublesome in that the cushion forces the blanked material back into the stock without allowing it to drop free. Various arrangements including doctor knives have been used to strip the material but have not always been successful.

It is an object of the present invention to provide a rotary-die stripping mechanism which utilizes pneumatic force to collect and discharge blanked material punched against the resilient cylinder.

Another object of this invention is to provide a cushion die cylinder arrangement for moving stock positively into a punching area of a rotary die, capturing and transporting the blanked material so punched for an interval and then allowing it to drop away by gravity when well clear of the punched stock.

Other objects and attendant advantages of this invention will become more readily apparent and understood from the following detailed specification and accompanying drawings in which:

FIG. 1 represents a front view, partly in section, of a rotary die stripping machine embodying principles of the invention; and

FIG. 2 is a vertical section of the machine taken on line 2-2 of FIG. 1.

Referring now to the details of the invention as shown in the drawings, reference numeral 10 indicates generally a rotary die machine. This machine 10 comprises a pair of contacting cylinders 12 and 14 rotated at a common speed together by a power source (not shown) through meshed gears 16 and 18. The uppermost or male cylinder 12 has sharp-edged punches 19 of any desired shape secured to its surface. The lower or female cylinder 14 has a resilient rubber face or cushion 20 which acts as a die.

This cylinder 14 is provided with spoked or perforated ends 22 and 24 so as to define a hollow chamber open to the atmosphere. It is driven at one end 22 by means of the gear 18, and a hollow axle and journal 26, the other end 24 being supported on another hollow axle and journal 28.

A pipe 30, secured for non-rotation, and communicating with a vacuum pump 32 (driven by motor 34), extends completely through the cylinder 14 and is supported by the hollow axles 26 and 28.

Upon this pipe 30 and within the cylinder 14, there is securely mounted a fixed sectorial chamber 36 consisting of a pair of sector ends 38 joined by a pair of baflle vanes 40 encompassing 1 to 120 degrees between them. The chamber 36 is positioned, as illustrated in FIG. 2, so as to face 90 degrees of its total 100 or 120 degrees toward the interior upper right quadrant of the female cylinder 14 and the remainder toward the upper left quadrant,

assuuming the operating direction of the machine 10 is as shown by the arrows.

Air holes 42 are formed in the pipe 30 to communicate the vacuum therein with the chamber 36. Other small air holes 44 through cylinder 14 and cushion face 20 are made at the places on its periphery corresponding to the impact areas of the punches 19. Alternately, the entire periphery of the cylinder 14 may be covered by a plurality of small air holes 44 and then masked off except for the areas above-mentioned.

In operation, the vacuum pump 32 maintains a constant negative pressure inside the sectorial chamber 36. Paper stock P directed into the rotating cylinders 12 and 14 is grasped by the vacuum force and transported into the cutting area where the blanks are formed by the punches 19 working against the resilient cushion face 20. The punched blanks B of material adhere by vacuum to its face and are thus extracted from the punched stock P' and carried around with cylinder 14 until they leave the vacuum quadrant and drop off. A doctor blade at reference point 46 is not essential but may be used, mainly to define the drop area especially at high speeds of operation of the machine 10.

Obviously many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. A rotary die machine for punching blanks in sheet material, comprising a first rotating cylinder having at least one punch mounted on its surface, a second rotating cylinder having a cushion face acting as a die for said punch and forming a nip with said first rotating cylinder for passage of said sheet material therethrough, said second rotating cylinder and cushion face each having an aperture in register with each other and with said punch, a vacuum source, and structure defining a stationary chamber Within said second rotating cylinder and communicating with said vacuum source so as to become a vacuum chamber, said vacuum chamber communicating with said aperture continuously from immediately upstream of said nip to a point downstream therefrom, whereby said sheet material is adhered against said cushion face when passing through said nip and the blank in said sheet material formed at said nip is adhered to said cushion face until reaching said point downstream of said nip, thereby separating said blank from said sheet material.

2. The rotary die machine of claim 1 wherein said vacuum chamber is defined longitudinally by a pair of baflle vanes and end-wise by a pair of sector ends.

3. The rotary die machine of claim 1 wherein said second rotating cylinder contains a hollow axle having lateral openings for communicating said vacuum source with said vacuum chamber.

4. The rotary die machine of claim 3 wherein hollow journals are provided for said hollow axle.

5. The rotary die machine of claim 1 wherein said vacuum chamber extends from 10 to 20 upstream of said nip.

6. The rotary die machine of claim 1 wherein said vacuum chamber extends downstream of said nip.

7. The rotary die machine of claim 1 wherein said first rotating cylinder has a plurality of said punches and said aperture in said second rotating cylinder and cushion face is provided for each punch of said plurality of punches.

8. The rotary die machine of claim 1 wherein the surface speed of said first rotating cylinder and said cushion face is the same.

9. The rotary die machine of claim 1 and additionally, means positioned at said point downstream of said nip for stripping said blank from said cushion face.

10. The rotary die machine of claim 1 wherein said second rotating cylinder and cushion face have a plusaid punch.

References Cited UNITED STATES PATENTS Hallman 83-100 X Ringel 93-36 Golding 83-100 X Schrader 83-100 ANDREW R. JUHASZ, Primary Examiner. 

1. A ROTARY DIE MACHINE FOR PUNCHING BLANKS IN SHEET MATERIAL, COMPRISING A FIRST ROTATING CYLINDER HAVING AT LEAST ONE PUNCH MOUNTED ON ITS SURFACE, A SECOND ROTATING CYLINDER HAVING A CUSHION FACE ACTING AS A DIE FOR SAID PUNCH AND FORMING A NIP WITH SAID FIRST ROTATING CYLINDER FOR PASSAGE OF SAID SHEET MATERIAL THERETHROUGH, SAID SECOND ROTATING CYLINDER AND CUSHION FACE EACH HAVING AN APERTURE IN REGISTER WITH EACH OTHER AND WITH SAID PUNCH, A VACUUM SOURCE, AND STRUCTURE DEFINING A STATIONARY CHAMBER WITHIN SAID SECOND ROTATING CYLINDER AND COMMUNICATING WITH SAID VACUUM SOURCE SO AS TO BECOME A VACUUM CHAMBER, SAID VACUUM CHAMBER COMMUNICATING WITH SAID APERTURE CONTINUOUSLY FROM IMMEDIATELY UPSTREAM OF SAID NIP TO A POINT DOWNSTREAM THEREFROM, WHEREBY SAID SHEET MATERIAL IS ADHERED AGAINST SAID CUSHION FACE WHEN PASSING THROUGH SAID NIP AND THE BLANK IN SAID SHEET MATERIAL FORMED AT SAID NIP IS ADHERED TO SAID SAID NIP, THEREBY SEPARATING SAID BLANK FROM SAID SHEET MATERIAL. 